As a suspension system including an electromagnetic actuator functioning as a shock absorber, namely, as the so-called electromagnetic suspension system, there is known one described in the following Patent Document 1, for instance. The electromagnetic suspension system has an advantage that a vibration of a sprung portion can be effectively damped based on a skyhook damper theory, and has been actively developed in the field of vehicles. At present, various proposals with regard to the control of the actuator have been made. In an electromagnetic suspension system described in the following Patent Document 2, there has been developed a control for compensating for an internal inertial force of the actuator.    Patent Document 1 WO 02/08001 A1    Patent Document 2 JP-A-2004-237825